When performing internal hydrostatic pressure tests of polymer tubes use is made of special end closures, which are mounted at opposite ends of a sample of the actual polymer tube in order to seal of the sample to be tested. One of the end closures is a so-called blind end closure part provided only with an air escape valve, while the opposite end closures is provided with an inlet valve system adapted to connect the testing tube sample with an external pressure testing equipment station during the internal hydrostatic pressure test. The pressure station is started while said air escape valve is open, when the sample is completely aired out, the test can be started.
Known end closures of the art in question are normally produces from moulded items by milling into the correct configuration and dimensions. Most often such end closures are divided into two or more parts being adapted to mount by assembling around opposite ends of the tube to be tested.
When it comes to very large end closures they are normally made by a moulded item made from an alloy of aluminium and bronze, which means that end closures for very large tubes having a diameter in the range of 2000-2500 mm are very heavy and very expensive to produce and indeed very difficult to handle and transport.